Fix putting of prototype transitions. The length is also subject to GC, just like entry.

BUG=347536
LOG=n
R=danno@chromium.org

Review URL: https://codereview.chromium.org/183193003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19586 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mark-compact.cc

@@ -2653,6 +2653,7 @@ void MarkCompactCollector::ClearNonLivePrototypeTransitions(Map* map) {
     Object* prototype = prototype_transitions->get(proto_offset + i * step);
     Object* cached_map = prototype_transitions->get(map_offset + i * step);
     if (IsMarked(prototype) && IsMarked(cached_map)) {
+      ASSERT(!prototype->IsUndefined());
       int proto_index = proto_offset + new_number_of_transitions * step;
       int map_index = map_offset + new_number_of_transitions * step;
       if (new_number_of_transitions != i) {

src/objects.cc

@@ -11559,7 +11559,7 @@ Handle<Map> Map::PutPrototypeTransition(Handle<Map> map,
 
   cache->set(entry + kProtoTransitionPrototypeOffset, *prototype);
   cache->set(entry + kProtoTransitionMapOffset, *target_map);
-  map->SetNumberOfProtoTransitions(transitions);
+  map->SetNumberOfProtoTransitions(last + 1);
 
   return map;
 }

test/mjsunit/regress/regress-put-prototype-transition.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --expose-gc --stress-compaction --gc-interval=255
+
+function deepEquals(a, b) { if (a === b) { if (a === 0) return (1 / a) === (1 / b); return true; } if (typeof a != typeof b) return false; if (typeof a == "number") return isNaN(a) && isNaN(b); if (typeof a !== "object" && typeof a !== "function") return false; var objectClass = classOf(a); if (objectClass !== classOf(b)) return false; if (objectClass === "RegExp") { return (a.toString() === b.toString()); } if (objectClass === "Function") return false; if (objectClass === "Array") { var elementCount = 0; if (a.length != b.length) { return false; } for (var i = 0; i < a.length; i++) { if (!deepEquals(a[i], b[i])) return false; } return true; } if (objectClass == "String" || objectClass == "Number" || objectClass == "Boolean" || objectClass == "Date") { if (a.valueOf() !== b.valueOf()) return false; } return deepObjectEquals(a, b); }
+assertSame = function assertSame(expected, found, name_opt) { if (found === expected) { if (expected !== 0 || (1 / expected) == (1 / found)) return; } else if ((expected !== expected) && (found !== found)) { return; } fail(PrettyPrint(expected), found, name_opt); }; assertEquals = function assertEquals(expected, found, name_opt) { if (!deepEquals(found, expected)) { fail(PrettyPrint(expected), found, name_opt); } };
+assertEqualsDelta = function assertEqualsDelta(expected, found, delta, name_opt) { assertTrue(Math.abs(expected - found) <= delta, name_opt); }; assertArrayEquals = function assertArrayEquals(expected, found, name_opt) { var start = ""; if (name_opt) { start = name_opt + " - "; } assertEquals(expected.length, found.length, start + "array length"); if (expected.length == found.length) { for (var i = 0; i < expected.length; ++i) { assertEquals(expected[i], found[i], start + "array element at index " + i); } } };
+assertTrue = function assertTrue(value, name_opt) { assertEquals(true, value, name_opt); };
+assertFalse = function assertFalse(value, name_opt) { assertEquals(false, value, name_opt); };
+// End stripped down and modified version of mjsunit.js.
+
+var __v_0 = {};
+var __v_1 = {};
+function __f_3() { }
+function __f_4(obj) {
+  for (var __v_2 = 0; __v_2 < 26; __v_2++) {
+    obj["__v_5" + __v_2] = 0;
+  }
+}
+function __f_0(__v_1, __v_6) {
+    (new __f_3()).__proto__ = __v_1;
+}
+%DebugPrint(undefined);
+function __f_1(__v_4, add_first, __v_6, same_map_as) {
+  var __v_1 = __v_4 ? new __f_3() : {};
+  assertTrue(%HasFastProperties(__v_1));
+  if (add_first) {
+    __f_4(__v_1);
+    assertFalse(%HasFastProperties(__v_1));
+    __f_0(__v_1, __v_6);
+    assertTrue(%HasFastProperties(__v_1));
+  } else {
+    __f_0(__v_1, __v_6);
+    assertTrue(%HasFastProperties(__v_1));
+    __f_4(__v_1);
+    assertFalse(%HasFastProperties(__v_1));
+  }
+}
+gc();
+for (var __v_2 = 0; __v_2 < 4; __v_2++) {
+  var __v_6 = ((__v_2 & 2) != 7);
+  var __v_4 = ((__v_2 & 2) != 0);
+  __f_1(__v_4, true, __v_6);
+  var __v_0 = __f_1(__v_4, false, __v_6);
+  __f_1(__v_4, false, __v_6, __v_0);
+}
+__v_5 = {a: 1, b: 2, c: 3};